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  1. Jamie
  2. Epsom Salt
  3. Saturday, June 10 2017, 06:04 AM
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I've become quite concerned that some of the impurities in the epsom salts I buy are possibly present at levels that are harmful. I've been doing some research into the issue but I'm far from an expert and still not sure if particularly the arsenic impurities could be bad for you. Would be most interested in peoples input on the quora question I have set up here :

I've summarised what I've understood so far in the 'answer wiki' of the quora question. Would be most grateful if others had more information to add. Particularly would the arsenic impurities in epsom salts be likely to be the less harmful pentavalent compounds or trivalent??

I live in Chiang Mai Thailand. The salts with the specification as in the quora question are all that are available to me at a reasonable price.

There are two possible methods for producing Magnesium Sulphate described here :


What is the level of arsenic in the water? 400 kg * 0.0001% = 400 mg per 700 liters = 571 micrograms / liter or 571 ppb

What type of arsenic is it likely to be pentavalent or trivalent? I assume that the arsenic is non-organic rather than an organic compound? Not sure if it would be pentavalent or trivalent. But this seems to be crucial as different types of arsenic compound are much more toxic and much more absorbable through human skin.

(From Arsenic Toxicity) The toxicity of arsenic compounds can vary greatly. In general, arsenic compounds can be ranked from highest to lowest toxicity:

inorganic trivalent compounds,

organic trivalent compounds,

inorganic pentavalent compounds,

organic pentavalent compounds, and

elemental arsenic [Gorby 1988].

What levels are safe to bathe in?

the EPA says now that arsenic levels in drinking water of less than 10 ppb are acceptable, they brought down their earlier recommendation of 50 ppb.

but this summary of research says that bathing for 30 minutes you are likely to absorb less than 1% of the arsenic you’d absorb if you were drinking contaminated liquids. It concludes that “The limited data from individuals using high arsenic water for bathing and other household uses while drinking bottled water do not demonstrate detectable absorption of arsenic from bathing.” This is for people bathing in arsenic contaminated well waters with similar levels of arsenic to what we might see in floatation tanks.

Arsenic might naturally occur in seawater at 24 ppb according to this source.

It has been estimated that the average daily dietary intake of arsenic by adults in the United States is 40 micrograms per day [ATSDR 2007]. See Arsenic Toxicity

Soil contains about 10 times the concentration of arsenic that the float tank water would (again from Arsenic Toxicity) :

The U.S. Geological Survey has mapped arsenic distribution in soils in the United States. For the Conterminous United States, the geometric mean arsenic level in soil is 5.2 parts per million (ppm). Soil levels in the Eastern United States (east of the 96th meridian) have a geometric mean of 4.8 ppm arsenic (range
  1. Kane Mantyla
  2. more than a month ago
I think there may be concerns with floating a lot, but not sure if it has to do with impurities. Maybe a more generic concern about being in an environment mostly unknown to the body/mind for extended durations and what its affects are. I suspect some case studies in the future.

I did reply to the quora post, and as your research shows (reposted below for viewer convenience), Arsenic in Epsom salt 0.0001% max. The body will absorb less than 1% transdermally than it would ingested. It would seem these two factors would place the concern of arsenic toxicity very very low.

I would love to see the research you compiled curated so we could add here as an article. That would be valuable to the community.
  1. Kane Mantyla
  2. more than a month ago
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